Suspension strut bearing

ABSTRACT

A bearing (1) for the wheel suspension strut of a motor vehicle has an inner and an outer bearing ring (2, 3). The inner bearing ring (2) radially encloses a clearance ring (5) concentrically arranged in its bore (4). A bearing housing (8) made of deep-drawn sheet metal encloses the outer bearing ring (3). In order to reduce the total mass of the bearing and to allow it to be easily linked to a neighboring part of the car body, the bearing housing (8) forms a single piece with a flange (9) that extends essentially transversely to the bearing axis (10). The flange has at least one bore and screw (12, 13) for securing the suspension strut bearing (1) to a neighboring part of the car body.

The invention concerns a suspension strut bearing for the suspension ofwheels in automotive vehicles comprising an inner bearing ring and anouter bearing ring which can be secured by means to a neighboring partof a vehicle body, the inner bearing ring radially surrounding atolerance ring arranged concentrically in a bore thereof, the saidbearing further comprising a bearing housing of deep drawn sheet metalwhich encloses the outer bearing ring, and a flange which extendsessentially crosswise to a bearing axis and is made in one piece withthe bearing housing.

A suspension strut bearing with a thin-walled one-piece housing isdescribed in DE-A 28 20 585. In this document considered to be speciesdefining, the outer bearing ring is surrounded in the peripheraldirection by a bush-like portion of the housing. This portion merges inthe axial direction into a radially extending flange for securing theprior art suspension strut bearing to a neighboring part of a vehiclebody. A disadvantage of this bearing is that considerable sheetthicknesses are required for obtaining a positionaly exact securing ofthe bearing to a neighboring part of a vehicle body. Sheet thicknessesof 5 mm which are commonly used in this region of a vehicle body are notdeep drawable with the required precision, or are so only at very highcosts. A possible danger is that the housing undergoes undesireddeformation on application of force. Moreover, the prior art documentdoes not indicate any measures for connecting the outer bearing ring inan adequately strong manner to the bush-like flange of the housing, andparticularly for fixing the outer bearing ring in the axial direction.In addition, no measures for an adequate sealing of the bearing can beinferred from the document.

Other solutions show a two-piece flange, for example with complicatedreinforcement inserts, or welded constructions with the knowndisadvantages, or again, structures with a relatively solid design ofthe bush-like portion (DE-A 39 42 652).

It is therefore the object of the invention to provide a suspensionstrut bearing of the initially described type in which theaforementioned disadvantages are eliminated and which particularlycomprises a simple-to-manufacture means for connection to a neighboringpart of a vehicle body which meets high requirements of both strengthand precision.

The invention achieves this object according to the characterizing partof claim 1 by the fact that the bearing housing comprises a crimping of180° in at least one region of its inner surface which bears against theouter bearing ring, the crimping extends at least over the entire outersurface of the outer bearing ring or over the front end thereof, anaxial positional fixing of the outer bearing ring is assured by anannular swaging of the inner surface of the bearing housing, and thecrimping merges directly into the flange. This flange has a sheetthickness suitable for deep drawing and can be stiffened by beads. Bythe choice of this sheet thickness, it is possible to make the flangeand the bearing housing in one piece from a sheet metal part. Thehitherto used welded joint involving detrimental microstructural changesin the edge regions of the welded joint is no longer required. The totalmass of the suspension strut bearing is reduced by the construction ofthe invention.

Advantageous developments in the invention form the subject matter ofthe sub-claims 2 to 4 and will be described more closely below.

From claim 2 it can be seen that the bearing housing is angled radiallyinwards starting from a cylindrical portion thereof which radiallysurrounds the outer bearing ring, and this angled portion merges into aradially outwards crimped portion to form the flange (FIG. 2). Thecrimpings described here and in claim 1 serve on the one hand topositionaly fix the outer bearing ring in the suspension strut bearingand on the other hand they serve for the stiffening of the entireconstruction.

In a further development of the invention according to claim 3, an innerbearing ring for the suspension strut bearing is made of a deep drawablematerial, preferably steel sheet, and a radially extending end surfaceof this inner bearing ring projecting axially out of the bore of thesuspension strut bearing simultaneously forms a support and a stop for adamping element extending through the bore of the suspension strutbearing. This likewise one-piece sheet metal embodiment makes thecomplicated multipiece constructions mainly used in the prior artsuperfluous. The mass of the suspension strut bearing of the inventionis thus further reduced and its manufacturing costs are minimized.

The tolerance ring described in claim 4 serves to assure an exactlyfitted reception of the damping element situated in its bore and isadvantageously made of a plastics material, particularly of a glassfibre reinforced polyamide, but other materials such as flexible and/orlightweight materials can also be used. The radial sealing ring whichbears against a flange of the tolerance ring can be made ofpolyurethane.

Two examples of embodiment of the invention are represented in thedrawings and will be described more closely below.

FIG. 1 is an axial section of a suspension strut bearing with a crimpingof the bearing housing in the region of the radial outer surface of theouter ring, and

FIG. 2 is an axial section corresponding to FIG. 1 with a crimping inthe region of an axial outer surface.

FIG. 1 shows a suspension strut bearing 1 of the invention comprising aninner bearing ring 2 and an outer bearing ring 3. The outer bearing ring3 is made in two parts. The inner bearing ring 2 is made of steel sheetand surrounds a tolerance ring 5 arranged concentrically in its bore 4,the raceway 6 of the inner bearing ring 2 being roller-burnished toreceive the balls 7. A bearing housing 8 of a deep drawable materialencloses the outer bearing ring 3. The bearing housing 8 at the sametime forms a flange 9 which extends substantially crosswise to a bearingaxis 10. At least one bore 12 for a screw 13 for securing the suspensionstrut bearing 1 to a neighboring part of a vehicle body is provided inthe radial outer region 11 of the flange 9 facing away from the bearingaxis 10.

The inner surface 14 of the bearing housing 8 which bears against theouter bearing ring 3 is reinforced by a crimping 15, in this case of180° . This crimping 15 extends substantially over the radial outersurface 16 of the outer bearing ring 3.

The outer bearing ring 3 is axially fixed by a swaging 17 of the innersurface 14 of the bearing housing 8, and the other front end 18 of theouter bearing ring 3 facing away from the swaging 17 bears against aradially inwards angled end region 19 of the inner surface 14 of thebearing housing 8. The bearing ring 3 can be made by stamping from awelded blank. Advantageously, the swaging 17 in the bearing housing 8 ismade as an annular swaging in the axial direction. The inner bearingring 2 of the suspension strut bearing 1 projects axially out of thebore 20 thereof and the projecting end surface 21 of the inner bearingring 2 forms a support and a stop for a damping element extendingthrough the bore 20 of the suspension strut bearing 1. Since such adamping element is sufficiently known, it will not be described moreclosely here.

The tolerance ring 5 made of a plastics material is mounted in the bore4 of the inner bearing ring 2 and comprises a radial flange 23 on whoseouter surface 24 a radial sealing ring 25, advantageously comprising twosealing lips 26, is fixed. These sealing lips 26 bear against a part ofthe inner surface 14 of the bearing housing 8 and seal the suspensionstrut bearing 1 permanently against leaking lubricant.

FIG. 2 shows another embodiment of the crimping 15 of the bearinghousing 8. In this case, the crimping 15 forms an axial contact surface27 for the outer bearing ring 3. A swaging 17 of the inner surface 14 ofthe bearing housing 8 is provided in this embodiment as well.

We claim:
 1. A suspension strut bearing (1) for the suspension of wheelsin automotive vehicles comprising an inner bearing ring (2) and an outerbearing ring (3) which can be secured by means (12, 13) to a neighboringpart of a vehicle body, the inner bearing ring (2) radially surroundinga tolerance ring (5) arranged concentrically in a bore (4) thereof, thesaid bearing further comprising a bearing housing (8) of deep drawnsheet metal which encloses the outer bearing ring (3), and a flange (9)which extends essentially crosswise to a bearing axis (10) and is madein one piece with the bearing housing (8), characterized in that thebearing housing (8) comprises a crimping (15) of 180° C. in at least oneregion of its inner surface (14) which bears against the outer bearingring (3), the crimping (15) extends at least over the entire outersurface (16) of the outer bearing ring (3) or over the front end (18)thereof, an axial positional fixing of the outer bearing ring (3) isassured by an annular swaging (17) of the inner surface (14) of thebearing housing (8), and the crimping (15) merges directly into theflange (9).
 2. A suspension strut bearing of claim 1 wherein the bearinghousing (8) is angled radially inward starting from a cylindricalportion (28) thereof which radially surrounds the outer bearing ring(3), and this angled portion merges into a radially outward crimpedportion to form the flange (9).
 3. A suspension strut bearing of claim 1wherein an inner bearing ring (2) for the suspension strut bearing (1)is made of a deep drawable material and a radially extending end surface(21) of this inner bearing ring (2) projecting axially out of the bore(20) of the suspension strut bearing simultaneously forms a support anda stop for a damping element extending through the bore (20) of thesuspension strut bearing (1).
 4. A suspension strut bearing of claim 1wherein the tolerance ring (5) comprises a radial flange (23) serving toreceive a radial sealing ring (25) comprising two sealing lips (26)which bear against the inner surface (14) of the bearing housing (8).